This invention relates to a process for removing color byproducts and residues from a colored ditertiarydodecyldisulfide (DTDDDS) stream by contacting the colored DTDDDS stream with ammonium hydroxide (NH4OH) to produce a DTDDDS product.
DTDDDS is produced by oxidation of tertiarydodecylmercaptan using air. During the production of DTDDDS, colored byproducts and residues may be produced yielding a colored DTDDDS stream. These colored byproducts and residues are difficult to remove in a plant environment. In addition, when the colored DTDDDS stream is filtered, it may fail to meet product color specification. Typically, the color specification for a DTDDDS product is about 1 to about 2 using a Gardner color test. The colored DTDDDS stream generally has a color of about 3 to about 6 using a Gardner color test.
An inventive solution has been discovered to remove the color byproducts and residues from the colored DTDDDS stream to produce a DTDDDS product.
It is an object of this invention to provide a process for removing color byproducts and residues from a colored DTDDDS stream to produce a DTDDDS product.
It is another object of this invention to provide a process for removing color byproducts and residues from a colored DTDDDS stream to produce a DTDDDS product wherein the color range of the DTDDDS product is about 1 to about 2 on a Gardner color test.
In accordance with this invention, a process for removing colored byproducts and residues from a colored DTDDDS stream is provided. The process comprises:
(a) Contacting NH4OH and the colored DTDDDS stream to produce a mixture;
(b) Water washing the mixture to produce a washed mixture;
(c) Separating the washed mixture to produce a byproduct stream and a wet DTDDDS product; and
(d) Drying the wet DTDDDS product to produce a DTDDDS product.
A process to remove color byproducts and residues from a colored DTDDDS stream to produce a DTDDDS product is provided, said process comprising:
(a) Contacting NH4OH and the colored DTDDDS stream to produce a mixture;
(b) Water washing the mixture to produce a washed mixture;
(c) Separating the washed mixture to produce a byproduct stream and a wet DTDDDS product, and
(d) Drying the wet DTDDDS product to produce the DTDDDS product.
The colored DTDDDS stream can be produced by any method known in the art. Typically the colored DTDDDS stream is produced by oxidation of tertiarydodecylmercaptan using air. Copper catalysts often are used in the production of DTDDDS. Generally, the colored DTDDDS stream produced has a color in a range of about 3 to about 6 utilizing a Gardner color test (ASTM D-1544). The color specification for the DTDDDS product is in a range of about 1 to about 2 on a Gardner color test and most preferably, the color specification is 1 on a Gardner color test.
The first step of the process is contacting NH4OH with the colored DTDDDS stream to produce a mixture. The contacting can be conducted by any method known in the art. Generally, a NH4OH solution containing about 25% to about 35% by weight NH3 is utilized. Preferably, the NH4OH solution contains about 28% to about 32% by weight NH3. Typically, the NH4OH and colored DTDDDS stream are contacted in a ratio of about 1 to about 2 parts NH4OH to about 100 parts of the colored DTDDDS stream.
Generally, the contacting of the NH4OH with the colored DTDDDS stream is conducted at a temperature range of about 80xc2x0 F. to about 125xc2x0 F., preferably at a temperature range of 85xc2x0 F. to 120xc2x0 F. The contacting of the NH4OH with the colored DTDDDS stream is for a duration of about 12 hours to about 72 hours. The duration of the contacting depends on the reactivity of the colored DTDDDS stream. Preferably, the duration of the contacting is from about 24 hours to about 48 hours. The contacting yields a mixture comprising DTDDDS, NH4OH, and color byproducts and residues.
The second step of the process is water washing the mixture to produce a washed mixture. Generally, a quantity of water ranging from about 10% to about 30% by weight of the colored DTDDDS stream is used. The NH4OH is soluble in water so the water wash can proceed rapidly. Typically, the water wash step is conducted at a temperature in a range of about 70xc2x0 F. to about 100xc2x0 F. The washed mixture comprises DTDDDS, NH4OH, water, and color byproducts and residues. The third step of the process is separating the washed mixture to produce a byproduct stream and a wet DTDDDS product. The separating occurs in a temperature range of about 70xc2x0 F. to about 100xc2x0 F. and over a period of time in a range of about 2 hours to about 72 hours. Preferably, the separating occurs over a period of time in a range from about 48 hours to about 72 hours. The separating can be completed in any type of process equipment. For example, the separating can be accomplished in a tank to remove the wet DTDDDS product. Then, wet DTDDDS product can be further separated by filtering, in order to remove water.
The fourth step of the process is drying the wet DTDDDS stream to produce a DTDDDS product with a color range of about 1 to about 2 on the Gardner color test and a moisture content of less than about 10 ppm by weight water. Preferably, the DTDDDS product has a Gardner color test number of 1 and a moisture content of less than 10 ppm by weight water. Drying can be conducted by any process known in the art. Generally, the wet DTDDDS stream is dried at a temperature in a range of about 70xc2x0 F. to about 100xc2x0 F. The drying is conducted for a duration sufficient to achieve a moisture content of less than 10 ppm by weight water. For example, drying can be accomplished by utilizing desiccant or a filtering system.